In the above-identified copending application and elsewhere, a transport and storage vessel for radioactive wastes, especially for irradiated nuclear reactor fuel elements, has been made known which comprises a chamber defined by upright walls, i.e. a receptacle shell, a receptacle bottom and a shielding cover of the plug type which fits within the mouth of the receptacle.
The shell of the vessel and the bottom are formed unitarily of cast iron, especially spherolitic cast iron, or cast steel, and the shell or walls are provided with a shoulder or flange configuration which can engage an outwardly extending flange on the plug-type shielding cover.
The cast alloy or body can be provided with cells in which radiation-absorbing materials can be received, these cells being, for example, so orientated and constructed that they block straight-line paths from the interior of the receptacle outwardly.
The radiation-shielding effect, however, is primarily a result of the thickness of the vessel shell and bottom and the thickness or height of the cover which not only must take up the static stresses of transport and storage, but must be sufficient to effect the predominant shielding or adsorption of the radiation from the radioactive wastes whether this radiation is gamma radiation or neutrons.
In the earlier transport or storage vessels for the aforedescribed purpose, the shielding cover is held in place by threaded bolts. This enables, prior to the insertion of the cover, the introduction of the radioactive wastes into the interior of the vessel.
The sealing between the shielding cover and the vessel walls is effective for long periods, but only as long as any sealing agent remains effective or the sealing structure formed by the flange arrangement remains effective.
While such systems have proved to be effective, they nevertheless do not provide a closure which is not dependent upon the sealing means between the shielding cover and the receptacle nor do they permit control of the sealing, i.e. ascertainment of a failure of the shielding-cover seal.